Cushion for decelerating falling bodies



pt. 3, 1968 T. o. OLSEN 3,399,407

CUSHION FOR DECELERATING FALLING BODIES Filed May 5, 1966 2 Sheets-Sheet1 Fig.1.

' 13:13.6, Thomas 0. Olsen Sept. 3, 1968 T. o. OLSEN CUSHION FORDECELERATING FALLING BODIES 2 Sheets-$heet 2 Filed May 5, 1966 INVENTORThomas 0 Olsen J ATrozzw ii United States Patent 3,399,407 CUSHION FORDECELERATING FALLING BODIES Thomas 0. Olsen, 910 S. Santa Fe, Salina,Kans. 67401 Filed May 3, 1966, Ser. No. 547,298 9 Claims. (Cl. -348)ABSTRACT OF THE DISCLOSURE A closed flexible bag having a conduitcommunicating with the bag and a continuously operating fan unit in theconduit for creating artificial currents of air to maintain the pressurein the bag at a predetermined level. Air expelled from the bag uponimpact of a falling object on the bag flows in a reverse directionthrough the fan unit to avoid pressure build up sufiicient to damage theobject.

This invention relates to a device for decelerating moving objects and,more particularly, to structure in the nature of a flexible, air filledbag adapted to be placed in the path of a moving object to bring theobject gently to rest without imparting severe impact and decelerationforces to the object.

Devices constructed pursuant to this invention have been found to beparticularly useful for cushioning the fall of pole vaulters and highjumpers in athletic meets wherein it is necessary to bring the bodies ofthe athletes to rest after the jump and, wherein it is extremelydesirable that the athletes not be subjected to shock or injury. Thedevice of this invention not only decelerates the athlete in a mannerwhich substantially eliminates shock, but it also has the additionaldesirable characteristic of being readily portable, permitting quick andeasy removal from the location of use to storage areas.

Heretofore, various materials, such as loose sand, sawdust and foamrubber or the like, have been used to cushion the fall of athletes invaulting and jumping events. All have the undesirable effect ofdecelerating the athlete in a manner which causes shock and stresseswhich can result in discomfort and even injury to the athlete. All ofthese materials are relatively non-portable. Attempts have been made toutilize a heap of separate pieces of foam rubber in a vaulting pit tominimize the shock of landing experienced by the vaulters. Althoughheaps of this material were much softer to the vaulter than were bags ormats of foam rubber as had been tried previously, the vaulter stillexperienced considerable shock upon landing on and compressing the foamrubber, and also huge heaps were required to cushion the fall,especially from substantial heights. Such huge heaps have presented amajor problem in installations where the vaulting or jumping pit had tobe disassembled after each meet and after each practice session in whichthe pits were used. Similarly, storage of the foam rubber pieces hasalso presented substantial problems.

Attempts have heretofore been made to utilize air cushions for thispurpose. Some such cushions have even included outlet orifices whichpermit escape of some of the air from the cushion after the air iscompressed to a predetermined pressure. An example of a cushion of thisgeneral type is shown and described in US. Letters Patent No. 2,975,855,issued Mar. 21, 1961. These devices attempted to relieve air pressure inthe cushion by metering the escape of air through relatively smallrestricted orifices. As a result, compression of the air in the cushionafter impact exceeded to such a degree that the vaulters body was met.with substantial resistance, causing the athlete to bounce andimparting considerable shock to his body.

It is the primary object of this invention to provide a device whichwill decelerate a moving object with little or no perceptible shock tothe object and which will not cause the object to be bounced as it isbrought gently to a condition of rest.

Another highly important object of the invention is to provide such adevice which is highly portable and can, therefore, be readily movedfrom place to place by one man.

Still other objects of this invention are to provide such a device whichis highly reliable, will not cause objects falling thereon to be pitchedoff its surface with resultant likelihood of injury, and which returnsto a ready condition in a very short period of time subsequent to eachuse made of the device.

These and other important objects of the invention will be pointed outor will become clear from a study of the drawings, specification andappended claims.

In the drawings:

FIGURE 1 is a front perspective view of the device of this invention,parts being broken away to reveal details of construction;

FIG. 2 is an enlarged, fragmentary, elevational sectional view of thedevice, a portion of the inflatable bag being broken away and appearingin cross section to reveal details of construction;

FIG. 3 is an enlarged, fragmentary, vertical sectional view taken online 3-3 of FIG. 2;

FIG. 4 is a fragmentary, vertical sectional view through the fan unit onthe same scale as FIG. 3, the fan blade and motor appearing inelevation;

FIG. 5 is a schematic, vertical sectional representation of the bag on areduced scale and illustrating the condition of the bag immediatelyafter impact of a person on the upper surface of the bag;

FIG. 6 is a view similar to FIG. 5 but illustrating the bag as theperson continues his descent by depressing the upper surface of the bag;

FIG. 7 is a view similar to FIGS. 5 and 6 but showing the generalconfiguration of the bag at substantially the time of completedeceleration of the person by the FIG. 8 is a view similar to FIG. 4 buton a reduced scale and illustrating a modified form of fan unit;

FIG. 9 is a view similar to FIG. 1 but illustrating a modified form ofbag and fan unit; and

FIG. 10 is an enlarged, fragmentary, vertical sectional view through thebag and fan unit shown in FIG. 9.

The preferred form of the invention is illustrated in FIGS. 14 whereinthe device 20 includes an inflatable body in the nature of a hollow,collapsible bag 22 of flexible material. Bag 22 has a top 23 presentingan upper impact surface 24, a front wall 26, a rear wall 28, side walls30 and 32, and a bottom wall 34.

Bag 22 is constructed from material which is relatively impervious tothe flow of air and it has been found that fabric of synthetic material,such as nylon or the like which has been impregnated with rubber,neoprene, plastic or other synthetic material, is well suited for thispurpose. The walls ofbag 22 may he joined together by any suitableprocess and, in the preferred construction, the walls are joined by theapplication of heat and pressure along the seams to provide a weld whichhas been found to be even stronger than stitching. The impregnatedfabric material comprising the walls of bag 22 is of relatively thin,highly flexible material and the synthetic fabric provides strength andresistance to deterioration and tearing stresses.

Rear wall 28 is provided with a port 36 which communicates with anelongated conduit 38, the latter having one end secured to the annularrim of port 36 as best illustrated in FIG. 2. Conduit 38 may be of anydesired length, and the opposite end of conduit 38 is secured to a fanunit 40. It will be seen in FIG. 4 of the drawings that unit 40 includesan annular tube 42 of sheet metal or the like. An annular rim 44 iswelded to the outer surface of tube 42 adjacent one end of the latter,and the outermost end of conduit 38 is telescoped over the marginal edgeof tube 42 and rim 44 where it is clamped to tube 42 by an annular clamp46. The latter is readily releasable to permit disassembly of unit 40from conduit 38 when the device is not in use. An annular slot 48 isprovided in tube 42 as illustrated best in FIG. 4, and a grill 50extends in covering relationship over slot 48 to permit ingress andegress of air through grill 50 while preventing foreign objects fromencountering a blade 52 forming an integral part of unit 40.

A standaid 54 welded to the inner surface of tube 42 provides a base orsupport for an electric motor 56 which drives blade 52 for a purpose tobe described hereinafter. The end 58 of tube 42 remote from conduit 38is open to permit the fiow of air in either direction in tube 42. Ifdesired, a pair of skids 60 may be welded to supporting legs 62 which,in turn, are welded to tube 42 of unit 40 for supporting the latter asillustrated in FIG. 1 of the drawings.

A plurality of flaps 64 are secured at spaced intervals to the undersideof top 23 and to the upper surface of bottom 34. It may be seen fromFIGS. 2 and 3 of the drawings that the flaps 64 for top 23 are locatedimmediately above the corresponding flaps 64 for bottom 34 so that cords66 may be tied to grommets 68 in the respective flaps 64 to extendvertically between a pair of corresponding flaps 64. Thus, cords 66provide spacers to maintain the shape of bag 22 substantially as shownin the drawings when the latter is inflated with air. The spacing of theflaps 64 may provide a somewhat tufted appearance to upper surface 24 ofbag 22, but the latter is maintained as a generally flat surface adaptedto receive thereon an object in motion for the purpose of cushioning anddecelerating the object.

It has been found that substantially inelastic cords 66 are preferableto elastic members for the purpose of maintaining the generallyrectangular configuration of bag 22 inasmuch as elastic members have atendency to yield and impart a motion to surface 24 after impact whichcauses bouncing of the object which impinges upon bag 22. Further, forease in manufacturing, it has been found desirable to utilize two cordsegments for construction of the cords 66, the segments being tiedtogether with a suitable knot. Manifestly, the adjustability affordedwith the use of the cord segments eliminates the necessity for closetolerances in manufacture and permits adjustment of the lengths of cords66 after assembly as may be necessary to insure that upper surface 24 ofbag 22 is essentially fiat and presents a reasonably level surface toreceive the object in motion without tending to cause the latter tobounce after impact.

In the embodiment illustrated in FIGS. 1-4, a pair of auxiliarywedge-shaped cushions 70 are secured to front wall 26 in mutually spacedrelationship, and each cushion 70 communicates with the interior of bag22 through relatively restricted orifices 72 in wall 26 as shown.Manifestly, the ends of the walls of cushions 72 proximal wall 26 aresecured to the letter in fluid-tight relationship by any suitable means.

The device chosen for illustration in FIGS. 1-4 is particularly suitedas a landing cushion for use in pole vaulting events wherein the uprightstandards (not shown) for supporting the vaulting crossbar are adaptedto be disposed immediately adjacent front wall 26 of bag 22. Thus, thecushions 70 extend forwardly from the device and on the side of thevaulting crossbar from which the vaulter will make his running approachduring the jump. The vaulting box (not shown) is disposed immediatelybetween the cushions 70.

Fan blade 52 is placed in motion by energizing motor 56 to impartartificial currents of air which are drawn through grill 50 and end 58of unit 40, and are forced through conduit 38 into bag 22. The diameterof conduit 38 and port 36 is relatively large in relationship to thevolumetric capacity of bag 22 so that the latter is inflated byoperation of fan unit 40 in a relatively short period of time. Blade 52is preferrably of the no overload type as will be well understood bythose familiar with the art, whereby the currents of air are forced intobag 22 until the air within the bag reaches a predetermined pressure,after which no further compression of the air in the bag is accomplishedeven though blade 52 continues to rotate. Unit 40 does not compress theair within bag 22 beyond a relatively low value intended primarily to besufficient merely to inflate the bag so that the latter is filled with aquantity of air at this low pressure. It has been found that a fancapable of compressing the air in bag 22 to a value of approximately .25inch of H 0 column is entirely adequate, and that compression to higherpressures is undesirable.

The air in bag 22 flows through orifices 72 to inflate the cushions 70.Thus, cushions 70 contain air at substantially the same pressure as theair in bag 22.

After the vaulter makes his jump, his body accelerates as he fallstoward upper surface 24 of bag 22. Thus, the body of the vaulter attainsa considerable amount of momentum by the time that initial contact ismade with surface 24. The vaulter is met with little resistance oninitial impact against surface 24 because of the extremely low pressureof the air within bag 22. However, as the vaulter strikes surface 24,the movement of his body depresses top 23 of the bag against the elasticquantity of air in the bag to begin cushioning the fall and decelerationof the vaulter. It is to be emphasized that the initial impact is verygentle upon the vaulters body and may be almost imperceptible because ofthe low pres sure of the quantity of air in the bag.

As further indentation is made in the bag by movement of the vaultersbody against surface 24, an increas ingly greater area of the latter isdepressed. This is schematically illustrated in FIGS. 5 and 6 of thedrawings. The pressing of top 23 downwardly into the bag causes anelevation of the pressure of the air within the bag. This elevatedpressure further retards movement of the vaulter and decelerates hisbody. At the same time, the elevated pressure very quickly causes thevolume of air initially in bag 22 to flow outwardly through thesubstantially large diameter conduit 38 past the continuously operatingfan blade 52. The almost instantaneous dumping of a large volume of airwithin bag 22, through port 36 and conduit 38, prevents the rise of airpressure within bag 22 to a value which would cause shock and impactivestresses to the vaulters body.

Further, the compression of air within bag 22 does not reach a pressurevalue which results in bounce of the body. Rather, the body is loweredcontinuously and gently toward bottom 34 of the bag. It has been foundthat a bag about 15 x 20' (exclusive of cushions 70) with a depthranging from 3' to 4 and having a port 2 in diameter, will lose air at asufficient rate following the impact of an average size vaulter in afall from approximately 16' so that the pressure within bag 22 neverexceeds approximately 2" of H 0 column while bringing the vaulter torest. This maximum pressure which is achieved when the vaulters body hastraversed approximately one-half the depth of bag 22, is not sufficientto cause more than mild stresses in the vaulters body, whereby thevaulter continues to receive the sensation of a very gentle and softdeceleration.

It will be apparent that a bag of somewhat smaller dimensions may beutilized for high jumping purposes. In such event, the size of port 36may be selectively varied to accommodate for objects having lessmomentum partially as a result of the fall from a lower height,maintaining the proportion necessary to achieve pressures substantiallyas described above.

The rate of evacuation of the air as the latter is squeezed from :bag 22continues to be suflicient as the velocity and momentum of the vaulterdecrease to avoid further pressure buildup and actually to lower thepressure of the air in bag 22 until the pressure again reachesapproximately .25 inch H O column as the body comes to rest or iscompletely decelerated and gravitates at a uniform rate toward bottomwall 34 of the bag. The pressure of .25 inch H O column is constantlymaintained by the continuous operation of unit 40 and insures that thevaulters :body is always resisted by air pressure and cannot proceed toimpact with bottom 34 with sufficient velocity to shock or injure thevaulter. It will be understood that the egress of air through conduit 38is always resisted by the continuously operating fan, but the nooverloadcharacteristics of the latter insure that egress past the fan ispossible at a rate to provide the enhanced damping of the momentum ofthe falling body as described above.

The position of the body of the vaulter after deceleration isschematically illustrated in FIG. 7 where it may be seen that asubstantial portion of the inner surface of bag 22 is caused to impingeupon the elastic air within the bag as the body approaches completedeceleration, whereby the force of even the low pressure air issuificient to counteract the weight of the body on the crumpled andpartially deflated bag. Thus, the forces of the air counterbalance theweight of the vaulter and tend to prevent complete movement of thelatter into contact with 'wall 34 of bag 22.

It has been found that the generally upright Walls 26, 28, 30 and 32 ofbag 22 enhance the operation of the latter for decelerating objectsstriking the surface 24 without a tendency to pitch the objects from thesurface where they could be injured by striking the ground. Further, therestraining cords 66 also limit any tendency of the device to pitch theobjects from the surface 24 after impact.

The cushions 70 are provided for breaking the fall of any vaulter whomight land short of the impacting surface 24 through the abortive vault,bro-ken pole or the like. These projecting cushions contain a quantityof low pressure air and, should the vaulters body hurl against either ofthe cushions, the escape of air from the cushion through the orifices 72is calculated to be of such a slow rate that the vaulter would beuninjured because of elasticity of the air partially entrapped in thecushion.

For cushions 70 containing approximately 48 cubic feet of air wheninflated, two 3" diameter orifices 72 for each cushion have been foundsatisfactory. The gentle deceleration characteristics described inconnection with bag 22 are not intended for short landings made on, orpartially on, cushions 70. Rather, the bounce available from the trappedair is desirable in such emergency situations so that there is atendency for the vaulter to be thrown or pitched toward the soft bag 22for further gentle deceleration. The partially trapped air in cushions70 operates as a barrier at the forward portion of the device whichtends to prevent collapse of bag 22 and particularly front wall 26,thereby urging the vaulters body rearwardly toward the soft landingportion of the bag. Yet, orifices 72 do permit metered escape of air tosoften the landing in a manner to prevent injury to the vaulter as aresult of landing short of the optimum location on bag 22.

The form of the invention illustrated in FIGS. 9 and 10 is similar tothat described above and includes a flexible bag 122 which may be of thesame material as that of bag 22. Bag 122, however, is provided withcompartmentalizing walls 166 at spaced intervals on the inside of bag122, and intersecting as illustrated. The walls 166 are provided with aplurality of slots 167 to permit substantially uninhibited flow of airwithin the interior of bag 122, yet the walls 166 maintain the desiredinflated shape of bag 122 to present a substantially flat impactivesurface 124. Further, the walls serve to provide the substantiallyvertical, outer edges of bag 122 to eliminate any tendency of an objectto be pitched from the surface 124 after impact.

A flexible conduit 138 communicates through a port 136 with the interiorof bag 122 similar to the construction of bag 22 as described above.However, conduit 138 communicates with an annular, rigid conduit 139 ofsheet metal or the like and of substantially the same diameter asconduit 138. The latter is clamped by a clamp 146 in telescopedrelationship with conduit 139 as illustrated in FIG. 10. A cylindricaltube 142 is partially telescoped in concentric relationship into theouter end of conduit 139 and is maintained by radially extending, rigidspacers 143 in axial alignment with conduit 139.

A fan unit, broadly designated 140, mounted within tube 142 providesartificial currents of air to inflate bag 122 through port 136, as willbe understood. Unit 140 operates continuously and at a speed to maintainthe pressure within bag 122 at a value in the range of the pressuredescribed with respect to device 20. As the air emanates from the innerend of tube 146, it follows a path generally as illustrated by thearrows in FIG. 10. Thus, as the air fans out, it moves toward the innersurface of conduit 139 and provides a moving air seal to prevent egressof slightly pressurized air from bag 122. However, when an objectimpacts upon surface 124, this moving air seal is readily overcome topermit egress of air out the open end of conduit 139 and around theouter surface of tube 142. Thus, it is not necessary for the air to passin a reverse direction by the rotating blade of unit 140. Rather, theair is provided with an auxiliary opening between the outer surface oftube 142 and the inner surface of conduit 139 for egress from the bag.

It will be noted that no auxiliary cushions are illustrated inconnection with bag 122. Obviously, if the latter were to be utilizedfor pole-vaulting purposes, such cushions would be desirable and couldbe provided substantially identical to cushions 70 as illustrated inconnection with bag 22. On the other hand, if these devices are to beused for cushioning the fall of high jumpers, it is preferable that nocushions be provided. It will be understood that device 20 could beconstructed without the provision of cushions 70 and orifices 72 forthis purpose.

Referring now to FIG. 8, a still further modified form of unit 240 forproviding artificial currents of air to the flexible bags isillustrated. Thus, unit 240 includes an elongated, rigid tube 242 inwhich is mounted en electric motor 256 having an elongated, axiallyextending, splined motor shaft 257. A standard 254 supports motor 256 intube 242 and radially extending spacer rods 259 support the end of shaft257 proximal the flexible conduit 238 as shown. A spring 261 betweenmotor 256 and blades 252 normally urges the blade into the positionillustrated in full lines in FIG. 8 forwardly of an annular slot 248 intube 242. When the pressure within the flexible bag connected to conduit238 reaches a maximum value, it acts against blade 252 to cause thelatter to shift against the bias of spring 261 along splined shaft 258to the position illustrated in dashed lines in FIG. 8. It will be notedthat this position is on the side of slot 248 remote from conduit 238and its connected flexible bag, whereby relatively unobstructed egressof large volumes of air is permitted through slot 248 withoutinterference by blade 252. When the pressure within the bag is againlowered to a value below that achieved during maximum pressure buildup,blade 252 is urged back into its normal position by spring 261 formaintaining the substantially low air pressure within the flexible bag.

One significant feature of all of the embodiments of this invention isthe rapid rate of recovery of the bags to their normal inflatedconditions following each use of the device for decelerating movingobjects. It has been found that for a bag of the dimensions describedabove utilizing a fan unit capable of achieving the pressures mentioned,the bag can be filled with air to such pressure in approximately 30seconds time. Thus, after each vault or jump there is no appreciabledelay until the subsequent vault or jump may take place. Further, afterthe device has been utilized, the fan unit can be disconnected from itssource of electrical energy. The bag can be quickly and easilydisconnected from the fan unit by means of the releasable clampfollowing which the bag unit can be immediately folded or rolled into ahighly compressed condition. This permits one man to carry the deflatedbag with one arm and the fan unit with the other for readytransportation to storage facilities. Manifestly, re-assembly of theunit for use can be quickly and easily accomplished.

It is to be emphasized that the theory of operation of the devices ofthis invention is to be distinguished from conventional cushions whichrely upon the ever increasing compression of the captive air in aflexible bag to accomplish deceleration of an object. Such devices havea tendency to achieve compression of the air to an amount which causesshock to the object and pitch or bounce which can injure a vaulter.

Further, devices of this kind which rely on limited metering of the airthrough an orifice to avoid excessive buildup of pressure, are highlysusceptible to destruction through inadvertent puncture of the flexiblematerial. On the other hand, it is not really important with the devicesof this invention that the material be absolutely impervious to the flowof air. So long as the punctures which do occur to the flexible bags arenot sufficiently great that the air pressure cannot achieve a valuewhich will distend the bag to its inflated condition, it will stilloperate satisfactorily for gently cushioning the fall of moving objects.Thus, vaulters or jumpers may use spiked shoes and the punctures whichmight be created from such use have a negligible effect inasmuch as thefan units are capable of producing whatever air flow may be required fordistending the bags.

It will also be appreciated that the devices of this invention do notnecessarily have to be utilized in horizontal positions for deceleratingfalling objects. On the contrary, the principles of the invention areequally applicable for decelerating moving objects which impinge uponthe surface of the bag as by throwing or the like, even though the bagmay not be in a horizontal position. Having thus described theinvention, what is claimed as new and desired to be secured by LettersPatent is: 1. A device for decelerating an object in motion comprising:t

a hollow, flexible, inflatable body having a conduit placing the sameinto communication with the atmosphere for flow of air into and out ofthe body,

said body having an impact surface for disposition within the path oftravel of said object, said surface being movable inwardly of the bodyin response to the force of said object thereagainst; and

fan means in said conduit rotatable continuously in a direction forholding said body norm-ally inflated with air from the atmosphere at aconstant pressure for damping said motion without shock to the objectstriking said surface,

said conduit and said fan means being adapted for escape of the air fromthe body while the fan means continue to rotate in said direction inresponse to said inward movement of the impact surface,

the air flow capacity of said conduit and said fan means beingproportioned to the mass and to the velocity of said object fordischarge of air from the body solely through said conduit at a rate torapidly relieve the body of pressure build-up resulting from initialimpact and thereby preclude rebound, yet restrict the egress of said airfrom the body through said conduit to cushion said object through theelasticity of the air in the body until the object comes to rest.

2. The invention of claim 1, said fan means having a no overload typeblade whereby currents of air are forced into said body until saidpressure is attained with no further compression of the air in the body.

3. The invention of claim 1,

one end of said conduit subjacent the body being open to the atmosphere,

said fan means being between the body and said one end of the conduit,

said conduit being elongated and of uniform crosssectional areathroughout its length.

4. The invention of claim 1, said fan means having blade means rotatableabout an axis parallel with the longitudinal axis of the conduit andwithin a plane normal to said axis of the conduit, presenting a barriernormally preventing escape of air from the body and yieldable to exhaustof air from the body in response to said pressure build-up.

5. The invention of claim 1,

said fan means having a blade reciprocable toward and away from saidbody; and

means yieldably holding the blade biased toward the body,

said conduit having an auxiliary opening between the ends of the path ofreciprocation of the blade for augmenting the flow of air into and outof the body,

6. The invention of claim 2,

a tube telescoped in said conduit at that end of the latter remote fromthe body,

said unit being housed in the tube,

said conduit having a larger diameter than that of the tube, presentingan auxiilary opening between the tube and the conduit to augment theflow of air through the tube.

7. The invention of claim 3, said conduit having an auxiliary opening toaugment the flow of air through said one end thereof.

8. The invention of claim 7, said auxiliary opening surrounding theconduit between said one end of the conduit and said fan means adjacentthe l-attter.

9. The invention of claim 3, said blade being shiftable toward and awayfrom said one end of the conduit; and means yieldably holding the bladebiased toward the body.

References Cited UNITED STATES PATENTS 3,310,818 3/1967 Fischer 53483,250,665 2/1967 Frost 56-329 3,128,480 4/ 1964 Lineback 5-348 2,975,8553/1961 Dudek 182-137 2,906,366 9/1959 Mapes 182--139 2,542,781 2/ 1951Sawyer 5-349 BOBBY R. GAY, Primary Examiner.

A. CALVERT, Assistant Examiner.

